/Engine/Plugins/Experimental/Water/Source/Runtime/Public/WaterUtils.h
Creates a transient render target of the proper size/format/... or returns the existing one if it's compatible. InRenderTarget is read-only so it's up to the caller to decide to update or not the RT. Usually, the calling code will be : RT =FWaterUtils::GetOrCreateTransientRenderTarget2D(RT, ...)
a compatible transient render target if InMaterialInterface is size/format/... is valid, nullptr otherwise
static [UTextureRenderTarget2D](API\Runtime\Engine\Engine\UTextureRenderTarget2D) * GetOrCreateTransientRenderTarget2D ( [UTextureRenderTarget2D](API\Runtime\Engine\Engine\UTextureRenderTarget2D) * InRenderTarget, [FName](API\Runtime\Core\UObject\FName) InRenderTargetName, const FIntPoint & InSize, ETextureRenderTargetFormat InFormat, const [FLinearColor](API\Runtime\Core\Math\FLinearColor) & InClearColor, bool bInAutoGenerateMipMaps )